Effects of an extreme temperature event on the behavior and age structure of an estuarine top predator, Carcharhinus leucas

The frequency of extreme environmental events is predicted to increase in the future. Understanding the short- and long-term impacts of these extreme events on large-bodied predators will provide insight into the spatial and temporal scales at which acute environmental disturbances in top-down processes may persist within and across ecosystems. Here, we use long-term studies of movements and age structure of an estuarine top predator—juvenile bull sharks Carcharhinus leucas—to identify the effects of an extreme ‘cold snap’ from 2 to 13 January 2010 over short (weeks) to intermediate (months) time scales. Juvenile bull sharks are typically year-round residents of the Shark River Estuary until they reach 3 to 5 yr of age. However, acoustic telemetry revealed that almost all sharks either permanently left the system or died during the cold snap. For 116 d after the cold snap, no sharks were detected in the system with telemetry or captured during longline sampling. Once sharks returned, both the size structure and abundance of the individuals present in the nursery had changed considerably. During 2010, individual longlines were 70% less likely to capture any sharks, and catch rates on successful longlines were 40% lower than during 2006−2009. Also, all sharks caught after the cold snap were young-of-the-year or neonates, suggesting that the majority of sharks in the estuary were new recruits and several cohorts had been largely lost from the nursery. The longer-term impacts of this change in bull shark abundance to the trophic dynamics of the estuary and the importance of episodic disturbances to bull shark population dynamics will require continued monitoring, but are of considerable interest because of the ecological roles of bull sharks within coastal estuaries and oceans.

Empire's children: Soviet childhood in the age of revolution

Ideas of childhood and citizenship stood at the center of the Soviet Union's empire-building project during the 1920s and 1930s. After the 1917 Revolution the Bolsheviks were faced with the challenge of establishing a new state structure and governing a vast territory inherited from its tsarist predecessor. In the early years of the Soviet project, new leaders enlisted a cadre of professionals tasked with not only creating the norms of childhood and the everyday, but also implementing policies to modernize habits and values of the empire's younger citizens. ^ To understand how children became a prime focus of Soviet imperial and ethno-cultural politics, my dissertation employs discourse analysis and compares the ways in which Soviet imperial policies were implemented in two ethnically different regions: the Buddhist Republic of Kalmykia as the colonial case study and Moscow as the Metropole. The current project examines newspapers, treatises, and inspectors' reports over the span of twenty years. It finds that the Bolsheviks' initial values and discourses in the realm of children's education, health, leisure and nutrition, all which were scientifically designed to transform children into ideal Soviet and modern citizens, changed over time as a result of the competing ideologies among local elites and the challenges they faced while intervening in children's everyday lives. ^ The most significant conclusion in this dissertation reveals that, contrary to previous scholarly arguments, the modernization projects that took place in Moscow and Kalmykia were more similar in the challenges and outcomes that local officials faced when implementing state policies.^

Empire's Children: Soviet Childhood in the Age of Revolution

Ideas of childhood and citizenship stood at the center of the Soviet Union’s empire-building project during the 1920s and 1930s. After the 1917 Revolution the Bolsheviks were faced with the challenge of establishing a new state structure and governing a vast territory inherited from its tsarist predecessor. In the early years of the Soviet project, new leaders enlisted a cadre of professionals tasked with not only creating the norms of childhood and the everyday, but also implementing policies to modernize habits and values of the empire’s younger citizens. To understand how children became a prime focus of Soviet imperial and ethno-cultural politics, my dissertation employs discourse analysis and compares the ways in which Soviet imperial policies were implemented in two ethnically different regions: the Buddhist Republic of Kalmykia as the colonial case study and Moscow as the Metropole. The current project examines newspapers, treatises, and inspectors’ reports over the span of twenty years. It finds that the Bolsheviks’ initial values and discourses in the realm of children’s education, health, leisure and nutrition, all which were scientifically designed to transform children into ideal Soviet and modern citizens, changed over time as a result of the competing ideologies among local elites and the challenges they faced while intervening in children’s everyday lives. The most significant conclusion in this dissertation reveals that, contrary to previous scholarly arguments, the modernization projects that took place in Moscow and Kalmykia were more similar in the challenges and outcomes that local officials faced when implementing state policies.